Storage optimization selection within a virtualization environment

ABSTRACT

Storage optimization selection for virtual disks of a virtualization environment, where the storage optimization can be selected based in part on the disk type of a virtual disk included in a virtual machine. The disk type of the virtual disk can be discovered by the virtualization environment which queries a database within the virtualization environment for metadata associated with the virtual disk. The metadata can be created when a virtual desktop infrastructure creates the virtual disk, and a virtual machine template that includes the at least one virtual disk. The virtual disk can be modified to either include or be associated with the metadata that describes a disk type of the virtual disk. Upon executing the virtual machine that includes the modified virtual disk, a storage subsystem of the virtualization environment can obtain the metadata of the virtual disk to discover the disk type of the virtual disk.

FIELD OF THE DISCLOSURE

This application generally relates to virtual machine configuration. Inparticular, this application relates to configuring a virtual diskwithin a virtual machine.

BACKGROUND OF THE DISCLOSURE

Virtual machines can typically access virtual disks that are configuredusing one or more storage optimizations. Configuring a virtual disk tohave a particular storage optimization often requires knowledge of thedisk type of the virtual disk. When a virtual machine is created, thetype of virtual disk to-be-included may not be known. In theseinstances, the virtual machine creator may not be able to choose aneffective storage optimization because the virtual machine creator maynot know the disk type of the virtual disk.

In virtual desktop infrastructure environments, virtual disks can be anydisk type. For example, a virtual disk can store an operating systemimage from which a virtual machine boots; or the virtual disk caninclude a non-persistent write-back cache that stores data that isinvalidated and destroyed when a virtual machine is rebooted. In someinstances, the virtual disk can be an image customization disk createdto pass through data and binaries that are used to customize a virtualmachine after that virtual machine boots. Different disk types oftenhave different properties, therefore these different disk types oftenmap to different disk storage optimizations.

Virtualization platforms often cannot identify the type of disk includedin a particular virtual machine. Rather, the system that creates thevirtual machine is often the only system that knows the disk type of thevirtual disk in a particular virtual machine. Selecting astorage-specific optimization can therefore be difficult for thevirtualization platform because the platform does not know what type ofvirtual disk is included in a particular virtual machine.

SUMMARY OF THE DISCLOSURE

In the broadest sense, this disclosure describes methods and systems forinforming a virtualization environment of the disk type of a virtualdisk included in a virtual machine. In many instances, thevirtualization environment does not know the disk type of a virtual diskwithin a virtual machine. Thus, the virtualization environment oftencannot adequately select a storage-specific optimization for the virtualmachine. By informing the virtualization environment of the disk type ofa virtual disk in a virtual machine, that virtualization environment canselect an appropriate storage-specific optimization for that virtualmachine.

In one aspect, described herein is a method for selecting storageoptimizations for a disk within a virtualization environment usingmetadata indicating a disk type of the disk. A virtual desktopinfrastructure executing on a computing machine creates a virtualmachine template comprising at least one virtual disk. The virtualdesktop infrastructure then modifies, responsive to creating the virtualmachine template, the at least one of the virtual disk to be associatedwith or comprise metadata describing a disk type of the at least onevirtual disk. A virtualization environment executes a virtual machinethat is created using the virtual machine template created by thevirtual desktop infrastructure. A storage subsystem of thevirtualization environment, obtains metadata of the at least one virtualdisk, and selects a storage optimization for the at least one virtualdisk based in part on the disk type described in the metadata.

In some embodiments, the method further includes copying the virtualmachine template to create a second virtual machine template comprisingthe at least one virtual disk comprising the metadata describing thedisk type.

In other embodiments, the method further includes attaching a storageoptimized according to the selected storage optimization.

In still other embodiments, the storage subsystem selects a storageoptimization based in part on the disk type and a specific disk storagetype. Modifying the virtual disk, in some embodiments, can furtherinclude modifying the virtual disk to be associated with or comprisemetadata to describe an operating system image disk type. In theseembodiments, the storage subsystem can select a storage optimizationcomprising creating a cache of the virtual disk.

In one embodiment, the virtual disk can be modified to be associatedwith or comprise metadata describing a non-persistent cache disk type.The storage subsystem, in this embodiment, can select a storageoptimization that comprises any one of re-order writes and early writeacknowledgements.

In another embodiment, the virtual disk can be modified to be associatedwith or comprise metadata describing an image customization disk type.The storage subsystem, in this embodiment, can select a storageoptimization that comprises security measures.

In another aspect, described herein is a system for selecting storageoptimizations for a disk within a virtualization environment usingmetadata indicating a disk type of the disk. The system includes avirtual desktop infrastructure that executes on a computing machine tocreate a virtual machine template comprising at least one virtual disk.The virtual desktop infrastructure then modifies, in response tocreating the virtual machine template, the at least one virtual disk tobe associated with or comprise metadata describing a disk type of the atleast one virtual disk. The system further includes a virtual machineexecuting within a virtualization environment, where the virtual machinecreated using the virtual machine template created by the virtualdesktop infrastructure. Also included is a storage subsystem thatexecutes within the virtualization environment to obtain the metadata ofthe at least one virtual disk. Upon obtaining the metadata, the storagesubsystem selects a storage optimization for the at least one virtualdisk based in part on the disk type described in the metadata.

BRIEF DESCRIPTION OF THE DRAWINGS

The following figures depict certain illustrative embodiments of themethods and systems described herein, in which like reference numeralsrefer to like elements. These depicted embodiments are to be understoodas illustrative of the disclosed methods and systems and not as limitingin any way.

FIG. 1A depicts embodiments of network environments that provide remoteaccess to computing devices that can execute application programs.

FIG. 1B and FIG. 1C are block diagrams that depict embodiments ofcomputing devices.

FIG. 2A and FIG. 2B are block diagrams that depict embodiments of avirtualization environment.

FIG. 3 is a block diagram that depicts embodiments of a virtualizationenvironment and a virtual desktop infrastructure environment.

FIG. 4A is a flow diagram that depicts an embodiment of a method formodifying a virtual disk.

FIG. 4B is a flow diagram that depicts an embodiment of a method forselecting a storage optimization.

DETAILED DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates one embodiment of a computing environment 101 thatincludes one or more client machines 102A-102N (generally referred toherein as “client machine(s) 102”) in communication with one or moreservers 106A-106N (generally referred to herein as “server(s) 106”).Installed in between the client machine(s) 102 and server(s) 106 is anetwork.

In one embodiment, the computing environment 101 can include anappliance installed between the server(s) 106 and client machine(s) 102.This appliance can mange client/server connections, and in some casescan load balance client connections amongst a plurality of backendservers.

The client machine(s) 102 can in some embodiment be referred to as asingle client machine 102 or a single group of client machines 102,while server(s) 106 may be referred to as a single server 106 or asingle group of servers 106. In one embodiment a single client machine102 communicates with more than one server 106, while in anotherembodiment a single server 106 communicates with more than one clientmachine 102. In yet another embodiment, a single client machine 102communicates with a single server 106.

A client machine 102 can, in some embodiments, be referenced by any oneof the following terms: client machine(s) 102; client(s); clientcomputer(s); client device(s); client computing device(s); localmachine; remote machine; client node(s); endpoint(s); endpoint node(s);or a second machine. The server 106, in some embodiments, may bereferenced by any one of the following terms: server(s), local machine;remote machine; server farm(s), host computing device(s), or a firstmachine(s).

In one embodiment, the client machine 102 can be a virtual machine 102C.The virtual machine 102C can be any virtual machine, while in someembodiments the virtual machine 102C can be any virtual machine managedby a hypervisor developed by XenSolutions, Citrix Systems, IBM, VMware,or any other hypervisor. In other embodiments, the virtual machine 102Ccan be managed by any hypervisor, while in still other embodiments, thevirtual machine 102C can be managed by a hypervisor executing on aserver 106 or a hypervisor executing on a client 102.

The client machine 102 can in some embodiments execute, operate orotherwise provide an application that can be any one of the following:software; a program; executable instructions; a virtual machine; ahypervisor; a web browser; a web-based client; a client-serverapplication; a thin-client computing client; an ActiveX control; a Javaapplet; software related to voice over internet protocol (VoIP)communications like a soft IP telephone; an application for streamingvideo and/or audio; an application for facilitating real-time-datacommunications; a HTTP client; a FTP client; an Oscar client; a Telnetclient; or any other set of executable instructions. Still otherembodiments include a client device 102 that displays application outputgenerated by an application remotely executing on a server 106 or otherremotely located machine. In these embodiments, the client device 102can display the application output in an application window, a browser,or other output window. In one embodiment, the application is a desktop,while in other embodiments the application is an application thatgenerates a desktop.

The server 106, in some embodiments, executes a remote presentationclient or other client or program that uses a thin-client orremote-display protocol to capture display output generated by anapplication executing on a server 106 and transmits the applicationdisplay output to a remote client 102. The thin-client or remote-displayprotocol can be any one of the following protocols: the IndependentComputing Architecture (ICA) protocol manufactured by Citrix Systems,Inc. of Ft. Lauderdale, Fla.; or the Remote Desktop Protocol (RDP)manufactured by the Microsoft Corporation of Redmond, Wash.

The computing environment 101 can include more than one server 106A-106Nsuch that the servers 106A-106N are logically grouped together into aserver farm 106. The server farm 106 can include servers 106 that aregeographically dispersed and logically grouped together in a server farm106, or servers 106 that are located proximate to each other andlogically grouped together in a server farm 106. Geographicallydispersed servers 106A-106N within a server farm 106 can, in someembodiments, communicate using a WAN, MAN, or LAN, where differentgeographic regions can be characterized as: different continents;different regions of a continent; different countries; different states;different cities; different campuses; different rooms; or anycombination of the preceding geographical locations. In some embodimentsthe server farm 106 may be administered as a single entity, while inother embodiments the server farm 106 can include multiple server farms106.

In some embodiments, a server farm 106 can include servers 106 thatexecute a substantially similar type of operating system platform (e.g.,WINDOWS NT, manufactured by Microsoft Corp. of Redmond, Wash., UNIX,LINUX, or SNOW LEOPARD.) In other embodiments, the server farm 106 caninclude a first group of servers 106 that execute a first type ofoperating system platform, and a second group of servers 106 thatexecute a second type of operating system platform. The server farm 106,in other embodiments, can include servers 106 that execute differenttypes of operating system platforms.

The server 106, in some embodiments, can be any server type. In otherembodiments, the server 106 can be any of the following server types: afile server; an application server; a web server; a proxy server; anappliance; a network appliance; a gateway; an application gateway; agateway server; a virtualization server; a deployment server; a SSL VPNserver; a firewall; a web server; an application server or as a masterapplication server; a server 106 executing an active directory; or aserver 106 executing an application acceleration program that providesfirewall functionality, application functionality, or load balancingfunctionality. In some embodiments, a server 106 may be a RADIUS serverthat includes a remote authentication dial-in user service. Inembodiments where the server 106 comprises an appliance, the server 106can be an appliance manufactured by any one of the followingmanufacturers: the Citrix Application Networking Group; Silver PeakSystems, Inc; Riverbed Technology, Inc.; F5 Networks, Inc.; or JuniperNetworks, Inc. Some embodiments include a first server 106A thatreceives requests from a client machine 102, forwards the request to asecond server 106B, and responds to the request generated by the clientmachine 102 with a response from the second server 106B. The firstserver 106A can acquire an enumeration of applications available to theclient machine 102 and well as address information associated with anapplication server 106 hosting an application identified within theenumeration of applications. The first server 106A can then present aresponse to the client's request using a web interface, and communicatedirectly with the client 102 to provide the client 102 with access to anidentified application.

The server 106 can, in some embodiments, execute any one of thefollowing applications: a thin-client application using a thin-clientprotocol to transmit application display data to a client; a remotedisplay presentation application; any portion of the CITRIX ACCESS SUITEby Citrix Systems, Inc. like the METAFRAME or CITRIX PRESENTATIONSERVER; MICROSOFT WINDOWS Terminal Services manufactured by theMicrosoft Corporation; or an ICA client, developed by Citrix Systems,Inc. Another embodiment includes a server 106 that is an applicationserver such as: an email server that provides email services such asMICROSOFT EXCHANGE manufactured by the Microsoft Corporation; a web orInternet server; a desktop sharing server; a collaboration server; orany other type of application server. Still other embodiments include aserver 106 that executes any one of the following types of hostedservers applications: GOTOMEETING provided by Citrix Online Division,Inc.; WEBEX provided by WebEx, Inc. of Santa Clara, Calif.; or MicrosoftOffice LIVE MEETING provided by Microsoft Corporation.

Client machines 102 can, in some embodiments, be a client node thatseeks access to resources provided by a server 106. In otherembodiments, the server 106 may provide clients 102 or client nodes withaccess to hosted resources. The server 106, in some embodiments,functions as a master node such that it communicates with one or moreclients 102 or servers 106. In some embodiments, the master node canidentify and provide address information associated with a server 106hosting a requested application, to one or more clients 102 or servers106. In still other embodiments, the master node can be a server farm106, a client 102, a cluster of client nodes 102, or an appliance.

One or more clients 102 and/or one or more servers 106 can transmit dataover a network 104 installed between machines and appliances within thecomputing environment 101. The network 104 can comprise one or moresub-networks, and can be installed between any combination of theclients 102, servers 106, computing machines and appliances includedwithin the computing environment 101. In some embodiments, the network104 can be: a local-area network (LAN); a metropolitan area network(MAN); a wide area network (WAN); a primary network 104 comprised ofmultiple sub-networks 104 located between the client machines 102 andthe servers 106; a primary public network 104 with a private sub-network104; a primary private network 104 with a public sub-network 104; or aprimary private network 104 with a private sub-network 104. Stillfurther embodiments include a network 104 that can be any of thefollowing network types: a point to point network; a broadcast network;a telecommunications network; a data communication network; a computernetwork; an ATM (Asynchronous Transfer Mode) network; a SONET(Synchronous Optical Network) network; a SDH (Synchronous DigitalHierarchy) network; a wireless network; a wireline network; or a network104 that includes a wireless link where the wireless link can be aninfrared channel or satellite band. The network topology of the network104 can differ within different embodiments, possible network topologiesinclude: a bus network topology; a star network topology; a ring networktopology; a repeater-based network topology; or a tiered-star networktopology. Additional embodiments may include a network 104 of mobiletelephone networks that use a protocol to communicate among mobiledevices, where the protocol can be any one of the following: AMPS; TDMA;CDMA; GSM; GPRS UMTS; or any other protocol able to transmit data amongmobile devices.

Illustrated in FIG. 1B is an embodiment of a computing device 100, wherethe client machine 102 and server 106 illustrated in FIG. 1A can bedeployed as and/or executed on any embodiment of the computing device100 illustrated and described herein. Included within the computingdevice 100 is a system bus 150 that communicates with the followingcomponents: a central processing unit 121; a main memory 122; storagememory 128; an input/output (I/O) controller 123; display devices124A-124N; an installation device 116; and a network interface 118. Inone embodiment, the storage memory 128 includes: an operating system,software routines, and a client agent 120. The I/O controller 123, insome embodiments, is further connected to a key board 126, and apointing device 127. Other embodiments may include an I/O controller 123connected to more than one input/output device 130A-130N.

FIG. 1C illustrates one embodiment of a computing device 100, where theclient machine 102 and server 106 illustrated in FIG. 1A can be deployedas and/or executed on any embodiment of the computing device 100illustrated and described herein. Included within the computing device100 is a system bus 150 that communicates with the following components:a bridge 170, and a first I/O device 130A. In another embodiment, thebridge 170 is in further communication with the main central processingunit 121, where the central processing unit 121 can further communicatewith a second I/O device 130B, a main memory 122, and a cache memory140. Included within the central processing unit 121, are I/O ports, amemory port 103, and a main processor.

Embodiments of the computing machine 100 can include a centralprocessing unit 121 characterized by any one of the following componentconfigurations: logic circuits that respond to and process instructionsfetched from the main memory unit 122; a microprocessor unit, such as:those manufactured by Intel Corporation; those manufactured by MotorolaCorporation; those manufactured by Transmeta Corporation of Santa Clara,Calif.; the RS/6000 processor such as those manufactured byInternational Business Machines; a processor such as those manufacturedby Advanced Micro Devices; or any other combination of logic circuits.Still other embodiments of the central processing unit 122 may includeany combination of the following: a microprocessor, a microcontroller, acentral processing unit with a single processing core, a centralprocessing unit with two processing cores, or a central processing unitwith more than one processing core.

While FIG. 1C illustrates a computing device 100 that includes a singlecentral processing unit 121, in some embodiments the computing device100 can include one or more processing units 121. In these embodiments,the computing device 100 may store and execute firmware or otherexecutable instructions that, when executed, direct the one or moreprocessing units 121 to simultaneously execute instructions or tosimultaneously execute instructions on a single piece of data. In otherembodiments, the computing device 100 may store and execute firmware orother executable instructions that, when executed, direct the one ormore processing units to each execute a section of a group ofinstructions. For example, each processing unit 121 may be instructed toexecute a portion of a program or a particular module within a program.

In some embodiments, the processing unit 121 can include one or moreprocessing cores. For example, the processing unit 121 may have twocores, four cores, eight cores, etc. In one embodiment, the processingunit 121 may comprise one or more parallel processing cores. Theprocessing cores of the processing unit 121, may in some embodimentsaccess available memory as a global address space, or in otherembodiments, memory within the computing device 100 can be segmented andassigned to a particular core within the processing unit 121. In oneembodiment, the one or more processing cores or processors in thecomputing device 100 can each access local memory. In still anotherembodiment, memory within the computing device 100 can be shared amongstone or more processors or processing cores, while other memory can beaccessed by particular processors or subsets of processors. Inembodiments where the computing device 100 includes more than oneprocessing unit, the multiple processing units can be included in asingle integrated circuit (IC). These multiple processors, in someembodiments, can be linked together by an internal high speed bus, whichmay be referred to as an element interconnect bus.

In embodiments where the computing device 100 includes one or moreprocessing units 121, or a processing unit 121 including one or moreprocessing cores, the processors can execute a single instructionsimultaneously on multiple pieces of data (SIMD), or in otherembodiments can execute multiple instructions simultaneously on multiplepieces of data (MIMD). In some embodiments, the computing device 100 caninclude any number of SIMD and MIMD processors.

The computing device 100, in some embodiments, can include a graphicsprocessor or a graphics processing unit (Not Shown). The graphicsprocessing unit can include any combination of software and hardware,and can further input graphics data and graphics instructions, render agraphic from the inputted data and instructions, and output the renderedgraphic. In some embodiments, the graphics processing unit can beincluded within the processing unit 121. In other embodiments, thecomputing device 100 can include one or more processing units 121, whereat least one processing unit 121 is dedicated to processing andrendering graphics.

One embodiment of the computing machine 100 includes a centralprocessing unit 121 that communicates with cache memory 140 via asecondary bus also known as a backside bus, while another embodiment ofthe computing machine 100 includes a central processing unit 121 thatcommunicates with cache memory via the system bus 150. The local systembus 150 can, in some embodiments, also be used by the central processingunit to communicate with more than one type of I/O device 130A-130N. Insome embodiments, the local system bus 150 can be any one of thefollowing types of buses: a VESA VL bus; an ISA bus; an EISA bus; aMicroChannel Architecture (MCA) bus; a PCI bus; a PCI-X bus; aPCI-Express bus; or a NuBus. Other embodiments of the computing machine100 include an I/O device 130A-130N that is a video display 124 thatcommunicates with the central processing unit 121. Still other versionsof the computing machine 100 include a processor 121 connected to an I/Odevice 130A-130N via any one of the following connections:HyperTransport, Rapid I/O, or InfiniBand. Further embodiments of thecomputing machine 100 include a processor 121 that communicates with oneI/O device 130A using a local interconnect bus and a second I/O device130B using a direct connection.

The computing device 100, in some embodiments, includes a main memoryunit 122 and cache memory 140. The cache memory 140 can be any memorytype, and in some embodiments can be any one of the following types ofmemory: SRAM; BSRAM; or EDRAM. Other embodiments include cache memory140 and a main memory unit 122 that can be any one of the followingtypes of memory: Static random access memory (SRAM), Burst SRAM orSynchBurst SRAM (BSRAM); Dynamic random access memory (DRAM); Fast PageMode DRAM (FPM DRAM); Enhanced DRAM (EDRAM), Extended Data Output RAM(EDO RAM); Extended Data Output DRAM (EDO DRAM); Burst Extended DataOutput DRAM (BEDO DRAM); Enhanced DRAM (EDRAM); synchronous DRAM(SDRAM); JEDEC SRAM; PC100 SDRAM; Double Data Rate SDRAM (DDR SDRAM);Enhanced SDRAM (ESDRAM); SyncLink DRAM (SLDRAM); Direct Rambus DRAM(DRDRAM); Ferroelectric RAM (FRAM); or any other type of memory. Furtherembodiments include a central processing unit 121 that can access themain memory 122 via: a system bus 150; a memory port 103; or any otherconnection, bus or port that allows the processor 121 to access memory122.

One embodiment of the computing device 100 provides support for any oneof the following installation devices 116: a CD-ROM drive, a CD-R/RWdrive, a DVD-ROM drive, tape drives of various formats, USB device, abootable medium, a bootable CD, a bootable CD for GNU/Linux distributionsuch as KNOPPIX®, a hard-drive or any other device suitable forinstalling applications or software. Applications can in someembodiments include a client agent 120, or any portion of a client agent120. The computing device 100 may further include a storage device 128that can be either one or more hard disk drives, or one or moreredundant arrays of independent disks; where the storage device isconfigured to store an operating system, software, programsapplications, or at least a portion of the client agent 120. A furtherembodiment of the computing device 100 includes an installation device116 that is used as the storage device 128.

The computing device 100 may further include a network interface 118 tointerface to a Local Area Network (LAN), Wide Area Network (WAN) or theInternet through a variety of connections including, but not limited to,standard telephone lines, LAN or WAN links (e.g., 802.11, T1, T3, 56 kb,X.25, SNA, DECNET), broadband connections (e.g., ISDN, Frame Relay, ATM,Gigabit Ethernet, Ethernet-over-SONET), wireless connections, or somecombination of any or all of the above. Connections can also beestablished using a variety of communication protocols (e.g., TCP/IP,TPX, SPX, NetBIOS, Ethernet, ARCNET, SONET, SDH, Fiber Distributed DataInterface (FDDI), RS232, RS485, IEEE 802.11, IEEE 802.11a, IEEE 802.11b,IEEE 802.11g, CDMA, GSM, WiMax and direct asynchronous connections). Oneversion of the computing device 100 includes a network interface 118able to communicate with additional computing devices 100′ via any typeand/or form of gateway or tunneling protocol such as Secure Socket Layer(SSL) or Transport Layer Security (TLS), or the Citrix Gateway Protocolmanufactured by Citrix Systems, Inc. Versions of the network interface118 can comprise any one of: a built-in network adapter; a networkinterface card; a PCMCIA network card; a card bus network adapter; awireless network adapter; a USB network adapter; a modem; or any otherdevice suitable for interfacing the computing device 100 to a networkcapable of communicating and performing the methods and systemsdescribed herein.

Embodiments of the computing device 100 include any one of the followingI/O devices 130A-130N: a keyboard 126; a pointing device 127; mice;trackpads; an optical pen; trackballs; microphones; drawing tablets;video displays; speakers; inkjet printers; laser printers; anddye-sublimation printers; or any other input/output device able toperform the methods and systems described herein. An I/O controller 123may in some embodiments connect to multiple I/O devices 103A-130N tocontrol the one or more I/O devices. Some embodiments of the I/O devices130A-130N may be configured to provide storage or an installation medium116, while others may provide a universal serial bus (USB) interface forreceiving USB storage devices such as the USB Flash Drive line ofdevices manufactured by Twintech Industry, Inc. Still other embodimentsinclude an I/O device 130 that may be a bridge between the system bus150 and an external communication bus, such as: a USB bus; an AppleDesktop Bus; an RS-232 serial connection; a SCSI bus; a FireWire bus; aFireWire 800 bus; an Ethernet bus; an AppleTalk bus; a Gigabit Ethernetbus; an Asynchronous Transfer Mode bus; a HIPPI bus; a Super WPM bus; aSerialPlus bus; a SCl/LAMP bus; a FibreChannel bus; or a Serial Attachedsmall computer system interface bus.

In some embodiments, the computing machine 100 can connect to multipledisplay devices 124A-124N, in other embodiments the computing device 100can connect to a single display device 124, while in still otherembodiments the computing device 100 connects to display devices124A-124N that are the same type or form of display, or to displaydevices that are different types or forms. Embodiments of the displaydevices 124A-124N can be supported and enabled by the following: one ormultiple I/O devices 130A-130N; the I/O controller 123; a combination ofI/O device(s) 130A-130N and the I/O controller 123; any combination ofhardware and software able to support a display device 124A-124N; anytype and/or form of video adapter, video card, driver, and/or library tointerface, communicate, connect or otherwise use the display devices124A-124N. The computing device 100 may in some embodiments beconfigured to use one or multiple display devices 124A-124N, theseconfigurations include: having multiple connectors to interface tomultiple display devices 124A-124N; having multiple video adapters, witheach video adapter connected to one or more of the display devices124A-124N; having an operating system configured to support multipledisplays 124A-124N; using circuits and software included within thecomputing device 100 to connect to and use multiple display devices124A-124N; and executing software on the main computing device 100 andmultiple secondary computing devices to enable the main computing device100 to use a secondary computing device's display as a display device124A-124N for the main computing device 100. Still other embodiments ofthe computing device 100 may include multiple display devices 124A-124Nprovided by multiple secondary computing devices and connected to themain computing device 100 via a network.

In some embodiments, the computing machine 100 can execute any operatingsystem, while in other embodiments the computing machine 100 can executeany of the following operating systems: versions of the MICROSOFTWINDOWS operating systems such as WINDOWS 3.x; WINDOWS 95; WINDOWS 98;WINDOWS 2000; WINDOWS NT 3.51; WINDOWS NT 4.0; WINDOWS CE; WINDOWS XP;and WINDOWS VISTA; the different releases of the Unix and Linuxoperating systems; any version of the MAC OS manufactured by AppleComputer; OS/2, manufactured by International Business Machines; anyembedded operating system; any real-time operating system; any opensource operating system; any proprietary operating system; any operatingsystems for mobile computing devices; or any other operating system. Instill another embodiment, the computing machine 100 can execute multipleoperating systems. For example, the computing machine 100 can executePARALLELS or another virtualization platform that can execute or managea virtual machine executing a first operating system, while thecomputing machine 100 executes a second operating system different fromthe first operating system.

The computing machine 100 can be embodied in any one of the followingcomputing devices: a computing workstation; a desktop computer; a laptopor notebook computer; a server; a handheld computer; a mobile telephone;a portable telecommunication device; a media playing device; a gamingsystem; a mobile computing device; a netbook; a device of the IPODfamily of devices manufactured by Apple Computer; any one of thePLAYSTATION family of devices manufactured by the Sony Corporation; anyone of the Nintendo family of devices manufactured by Nintendo Co; anyone of the XBOX family of devices manufactured by the MicrosoftCorporation; or any other type and/or form of computing,telecommunications or media device that is capable of communication andthat has sufficient processor power and memory capacity to perform themethods and systems described herein. In other embodiments the computingmachine 100 can be a mobile device such as any one of the followingmobile devices: a JAVA-enabled cellular telephone or personal digitalassistant (PDA), such as the i55sr, i58sr, i85s, i88s, i90c, i95cl, orthe im1100, all of which are manufactured by Motorola Corp; the 6035 orthe 7135, manufactured by Kyocera; the i300 or i330, manufactured bySamsung Electronics Co., Ltd; the TREO 180, 270, 600, 650, 680, 700p,700w, or 750 smart phone manufactured by Palm, Inc; any computing devicethat has different processors, operating systems, and input devicesconsistent with the device; or any other mobile computing device capableof performing the methods and systems described herein. In still otherembodiments, the computing device 100 can be any one of the followingmobile computing devices: any one series of Blackberry, or otherhandheld device manufactured by Research In Motion Limited; the iPhonemanufactured by Apple Computer; Palm Pre; a Pocket PC; a Pocket PCPhone; or any other handheld mobile device.

Illustrated in FIG. 2A is one embodiment of a virtualizationenvironment. Included on a computing device 201 is a hardware layer thatcan include one or more physical disks 204, one or more physical devices206, one or more physical processors 208 and a physical memory 216. Insome embodiments, firmware 212 can be stored within a memory element inthe physical memory 216 and can be executed by one or more of thephysical processors 208. The computing device 201 can further include anoperating system 214 that can be stored in a memory element in thephysical memory 216 and executed by one or more of the physicalprocessors 208. Still further, a hypervisor 202 can be stored in amemory element in the physical memory 216 and can be executed by one ormore of the physical processors 208. Executing on one or more of thephysical processors 208 can be one or more virtual machines 232A-C(generally 232). Each virtual machine 232 can have a virtual disk 226A-Cand a virtual processor 228A-C. In some embodiments, a first virtualmachine 232A can execute, on a virtual processor 228A, a control program220 that includes a tools stack 224. In other embodiments, one or morevirtual machines 232B-C can executed, on a virtual processor 228B-C, aguest operating system 230A-B.

Further referring to FIG. 2A, and in more detail, in one embodiment thevirtualization environment described includes a Type 2 hypervisor 202,or a hypervisor that executes within an operating system 214 executingon the computing device 201. A Type 2 hypervisor, in some embodiments,executes within an operating system 214 environment and virtual machinesexecute at a level above the hypervisor. In many embodiments, the Type 2hypervisor executes within the context of a user's operating system suchthat the Type 2 hypervisor interacts with the user's operating system.

In some embodiments, the virtualization environment includes a computingdevice 201. The computing device 201 can be any computing device, and insome embodiments the computing device 201 can be any computer, device orcomputing machine described herein. While FIG. 2A illustrates a singlecomputing device 201, in some embodiments the modules, programs, virtualmachines, and commands stored and executed by the computing device 201can be executed by more than one computing device 201. In still otherembodiments, the computing device 201 can be a server farm.

In one embodiment, the computing device 201 can include a hardware layer210 that includes one or more pieces of hardware that communicates withthe computing machine 201. In some embodiments, the hardware layer 210can include any hardware included in the computing device 201. In otherembodiments, the hardware layer 210 can include one or more physicaldisks 204, one or more physical devices 206, one or more physicalprocessors 208 and memory 216.

The hardware layer 210, in some embodiments, can include one or morephysical disks 204. A physical disk 204 can be any hard disk, while insome embodiments a physical disk 204 can be any hard disk describedherein. In some embodiments, the hardware layer 210 can include onephysical disk 204. In other embodiments, the hardware layer 210 caninclude more than one physical disk 204. The computing device 201, insome embodiments, can communicate with an external hard disk that isincluded in the hardware layer 210 as a physical disk 204.

In other embodiments, the hardware layer 210 can include a processor208. The processor 208, in some embodiments, can be any processor, whilein other embodiments the processor 208 can be any processor describedherein. The processor 208 can include one or more processing cores. Inother embodiments the computing device 201 can include one or moreprocessors 208. In some embodiments, the computing device 201 caninclude one or more different processors, e.g. a processing unit, agraphics processing unit, or a physics engine.

Physical devices 206, in some embodiments, can be any device included inthe computing device 201. In some embodiments, physical devices 206 canbe any combination of devices included in the computing device 201 andexternal devices that communicate with the computing device 201. Thecomputing device 201, in some embodiments, can include one or morephysical devices 206. A physical device 206 can be any of the following:a network interface card; a video card; a keyboard; a mouse; an inputdevice; a monitor; a display device; speakers; an optical drive; astorage device; a universal serial bus connection; any device connectedto the computing device 201; any device communicating with the computingdevice 201; a printer; a scanner; or any other device or devicedescribed herein.

The hardware layer 210 can further include physical memory 216 that caninclude any type of memory. In some embodiments, the physical memory 216can include any memory type described herein. The physical memory 216can store data, and in some embodiments can store one or more programs,or set of executable instructions. FIG. 2A illustrates one embodimentwhere firmware 212 is stored within the physical memory 216 of thecomputing device 201. Programs or executable instructions stored in thephysical memory 216 can be executed by the one or more processors 208 ofthe computing device 201.

Firmware 212, in some embodiments, can be any combination of executableinstructions and hardware that controls hardware communicating with orincluded within the computing device 201. In some embodiments, thefirmware 212 can control one or more pieces of hardware within thehardware layer 210. Firmware 212, in many embodiments, can be executedby one or more processors 208 within the computing device 201. In someembodiments, the firmware 212 can be boot firmware such as the basicinput/output system (BIOS.) Additional firmware 212 executing on thecomputing device 201 can interface with the BIOS.

In one embodiment, the computing device 201 can include an operatingsystem 214 executed by one or more physical processors 208. In someembodiments, the operating system 214 is a user operating system thatcan directly access the hardware devices in the hardware layer 210. Theoperating system 214 can be any operating system and in someembodiments, the operating system 214 can be any operating systemdescribed herein. FIG. 2A illustrates one embodiment where thehypervisor 202 executes within the context of the operating system 214executing on the computing device 201. In this embodiment, the operatingsystem 214 can be referred to as a host operating system 214, while theother operating systems can be referred to as guest operating systems.Guest operating systems can include the guest operating systems 230A-Bexecuting on the virtual machines 232, and/or the control program 220.

In some embodiments, the computing device 201 can include a hypervisor202. A hypervisor 202, in some embodiments, can be a program thatexecuted by processors 208 on the computing device 201 to manage anynumber of virtual machines. The hypervisor 202 can be referred to as avirtual machine monitor, or platform virtualization software. In someembodiments, a hypervisor 202 can be any combination of executableinstructions and hardware that monitors virtual machines executing on acomputing machine. While FIG. 2A illustrates a virtualizationenvironment that includes a Type 2 hypervisor 202, the computing device201 can execute any other type of hypervisor. For example, the computingdevice 201 can execute a virtualization environment that includes a Type1 hypervisor 202. In some embodiments, the computing device 201 canexecute one or more hypervisors 202. These one or more hypervisors 202can be the same type of hypervisor, or in other embodiments can bedifferent hypervisor types.

The hypervisor 202, in some embodiments, can provide virtual resourcesto operating systems 230 or control programs 220 executing on virtualmachines 232 in any manner that simulates the operating systems 230 orcontrol programs 220 having direct access to system resources. Systemresources can include: physical devices; physical disks; physicalprocessors; physical memory 216 and any other component included in thecomputing device 201 hardware layer 210. In these embodiments, thehypervisor 202 may be used to emulate virtual hardware, partitionphysical hardware, virtualize physical hardware, or execute virtualmachines that provide access to computing environments. In still otherembodiments, the hypervisor 202 controls processor scheduling and memorypartitioning for a virtual machine 232 executing on the computing device201. Hypervisor 202 may include those manufactured by VMWare, Inc., ofPalo Alto, Calif.; the XEN hypervisor, an open source product whosedevelopment is overseen by the open source Xen.org community; HyperV,VirtualServer or virtual PC hypervisors provided by Microsoft, orothers. In some embodiments, a computing device 201 executes ahypervisor 202 that creates a virtual machine platform on which guestoperating systems may execute. In these embodiments, the computingdevice 201 can be referred to as a host server. An example of such acomputing device is the XEN SERVER provided by Citrix Systems, Inc., ofFort Lauderdale, Fla.

In one embodiment, the hypervisor 202 can create a virtual machine232A-B (generally 232) in which an operating system 230 executes. In oneof these embodiments, for example, the hypervisor 202 loads a virtualmachine image to create a virtual machine 232. In another of theseembodiments, the hypervisor 202 executes an operating system 230 withinthe virtual machine 232. In still another of these embodiments, thevirtual machine 232 executes an operating system 230.

In one embodiment, the hypervisor 202 controls the execution of at leastone virtual machine 232. In another embodiment, the hypervisor 202presents at least one virtual machine 232 with an abstraction of atleast one hardware resource provided by the computing device 201. Theabstraction can further be referred to as a virtualization or virtualview of the hardware, memory processor and other system resourcesavailable on the computing device 201. Hardware or hardware resources,in some embodiments, can be any hardware resource available within thehardware layer 210. In other embodiments, the hypervisor 202 controlsthe manner in which virtual machines 232 access the physical processors208 available in the computing device 201. Controlling access to thephysical processors 208 can include determining whether a virtualmachine 232 should have access to a processor 208, and how physicalprocessor capabilities are presented to the virtual machine 232.

In some embodiments, the computing device 201 can host or execute one ormore virtual machines 232. A virtual machine 232 can be called a domain,a guest and/or a DOMAIN U. A virtual machine 232 is a set of executableinstructions that, when executed by a processor 208, imitate theoperation of a physical computer such that the virtual machine 232 canexecute programs and processes much like a physical computing device.While FIG. 2A illustrates an embodiment where a computing device 201hosts three virtual machines 232, in other embodiments the computingdevice 201 can host any number of virtual machines 232. The hypervisor202, in some embodiments, provides each virtual machine 232 with aunique virtual view of the physical hardware, memory, processor andother system resources available to that virtual machine 232. In someembodiments, the unique virtual view can be based on any of thefollowing: virtual machine permissions; application of a policy engineto one or more virtual machine identifiers; the user accessing a virtualmachine; the applications executing on a virtual machine; networksaccessed by a virtual machine; or any other similar criteria. Thehypervisor 202, in other embodiments, provides each virtual machine 232with a substantially similar virtual view of the physical hardware,memory, processor and other system resources available to the virtualmachines 232.

Each virtual machine 232 can include a virtual disk 226A-C (generally226) and a virtual processor 228A-C (generally 228.) The virtual disk226, in some embodiments, is a virtualized view of one or more physicaldisks 204 of the computing device 201, or a portion of one or morephysical disks 204 of the computing device 201. The virtualized view ofthe physical disks 204 can be generated, provided and managed by thehypervisor 202. In some embodiments, the hypervisor 202 provides eachvirtual machine 232 with a unique view of the physical disks 204. Thus,in these embodiments, the virtual disk 226 included in each virtualmachine 232 can be unique when compared with the other virtual disks226.

A virtual processor 228 can be a virtualized view of one or morephysical processors 208 of the computing device 201. In someembodiments, the virtualized view of the physical processors 208 can begenerated, provided and managed by the hypervisor 202. In someembodiments, the virtual processor 228 has substantially all of the samecharacteristics of at least one physical processor 208. In otherembodiments, the virtual processor 208 provides a modified view of thephysical processors 208 such that at least some of the characteristicsof the virtual processor 228 are different than the characteristics ofthe corresponding physical processor 208.

A control program 220 may execute at least one application for managingand configuring the guest operating systems executing on the virtualmachines 232 and in some embodiments the computing device 201. In someembodiments, the control program 220 can be called a control operatingsystem, a control domain, domain 0 or dom 0. The control program 220, insome embodiments, can be DOMAIN o or DOM0 of the XEN hypervisor. Thecontrol program 220 can execute an administrative application or programthat can further display a user interface which administrators can useto access the functionality of each virtual machine 232 and/or to managethe virtual machines 232. In some embodiments, the user interfacegenerated by the administrative program can be used to terminate theexecution of virtual machines 232, allocate resources to virtualmachines 232, assign permissions to virtual machines 232, or managesecurity credentials associated with virtual machines 232. The controlprogram 220, in some embodiments, can start new virtual machines 232 orterminate execution of executing virtual machines 232. In otherembodiments, the control program 220 can directly access hardware and/orresources within the hardware layer 210. In still another embodiment,the control program 220 can interface with programs and applicationsexecuting on the computing device 210 and outside of the context of avirtual machine 232. Similarly, the control program 220 can interfacewith programs and applications executing within the context of a virtualmachine 232.

In one embodiment, the hypervisor 202 can execute the control program220 within a virtual machine 232. The hypervisor 202 can create andstart the virtual machine 232. In embodiments where the hypervisor 202executes the control program 220 within a virtual machine 232, thatvirtual machine 232 can be referred to as the control virtual machine232. In still another embodiment, the control program 220 executeswithin a virtual machine 232 that is authorized to directly accessphysical resources on the computing device 201.

In some embodiments, a control program 220A (Not Shown) on a firstcomputing device 201A (Not Shown) may exchange data with a controlprogram 220B (Not Shown) on a second computing device 201B (Not Shown).In these embodiments the first computing device 201A may be locatedremote from the second computing device 201B. The control programs220A-B can exchange data via a communication link between a hypervisor202A (Not Shown) executing on the first computing device 201A and ahypervisor 202B (Not Shown) executing on the second computing device201B. Through this communication link, the computing devices 201A-B canexchange data regarding processors and other physical resourcesavailable in a pool of resources. Further, through this connectionbetween hypervisors 202A-B, the hypervisors 202A-B can manage a pool ofresources, e.g. the resources available on the first computing device201A and the second computing device 201B, distributed across one ormore computing devices 201A-B. The hypervisors 202A-B can furthervirtualize these resources and make them available to virtual machines232 executing on the computing devices 201A-B. In another instance ofthis embodiment, a single hypervisor 202 can manage and control virtualmachines 232 executing on both computing devices 201A-B.

In some embodiments, the control program 220 interacts with one or moreguest operating systems 230A-B (generally 230.) The control program 220can communicate with the guest operating systems 230 through ahypervisor 202. Through the hypervisor 202, the guest operating system230 can request access to physical disks 204, physical processors 208,memory 216, physical devices 206 and any other component in the hardwarelayer 210. In still other embodiments, the guest operating systems 230can communicate with the control program 220 via a communication channelestablished by the hypervisor 202, such as, for example, via a pluralityof shared memory pages made available by the hypervisor 202.

In some embodiments, the control program 220 includes a network back-enddriver for communicating directly with networking hardware provided bythe computing device 201. In one of these embodiments, the networkback-end driver processes at least one virtual machine request from atleast one guest operating system 230. In other embodiments, the controlprogram 220 includes a block back-end driver for communicating with astorage element on the computing device 201. In one of theseembodiments, the block back-end driver reads and writes data from thestorage element based upon at least one request received from a guestoperating system 230.

In another embodiment, the control program 220 includes a tools stack224. In another embodiment, a tools stack 224 provides functionality forinteracting with the hypervisor 202, communicating with other controlprograms 220 (for example, on a second computing device 201B), ormanaging virtual machines 232 on the computing device 201. In anotherembodiment, the tools stack 224 includes customized applications forproviding improved management functionality to an administrator of avirtual machine farm. In some embodiments, at least one of the toolsstack 224 and the control program 220 include a management API thatprovides an interface for remotely configuring and controlling virtualmachines 232 running on a computing device 201. In other embodiments,the control program 220 communicates with the hypervisor 202 through thetools stack 224.

In one embodiment, the hypervisor 202 executes a guest operating system230 within a virtual machine 232 created by the hypervisor 202. Inanother embodiment, the guest operating system 230 provides a user ofthe computing device 201 with access to resources within a computingenvironment. In still another embodiment, a resource includes a program,an application, a document, a file, a plurality of applications, aplurality of files, an executable program file, a desktop environment, acomputing environment, or other resource made available to a user of thecomputing device 201. In yet another embodiment, the resource may bedelivered to the computing device 201 via a plurality of access methodsincluding, but not limited to, conventional installation directly on thecomputing device 201, delivery to the computing device 201 via a methodfor application streaming, delivery to the computing device 201 ofoutput data generated by an execution of the resource on a secondcomputing device 201′ and communicated to the computing device 201 via apresentation layer protocol, delivery to the computing device 201 ofoutput data generated by an execution of the resource via a virtualmachine executing on a second computing device 201′, or execution from aremovable storage device connected to the computing device 201, such asa USB device, or via a virtual machine executing on the computing device201 and generating output data. In some embodiments, the computingdevice 201 transmits output data generated by the execution of theresource to another computing device 201′.

In one embodiment, the guest operating system 230, in conjunction withthe virtual machine on which it executes, forms a fully-virtualizedvirtual machine that is not aware that it is a virtual machine; such amachine may be referred to as a “Domain U HVM (Hardware Virtual Machine)virtual machine” In another embodiment, a fully-virtualized machineincludes software emulating a Basic Input/Output System (BIOS) in orderto execute an operating system within the fully-virtualized machine. Instill another embodiment, a fully-virtualized machine may include adriver that provides functionality by communicating with the hypervisor202. In such an embodiment, the driver is typically aware that itexecutes within a virtualized environment.

In another embodiment, the guest operating system 230, in conjunctionwith the virtual machine on which it executes, forms a paravirtualizedvirtual machine, which is aware that it is a virtual machine; such amachine may be referred to as a “Domain U PV virtual machine”. Inanother embodiment, a paravirtualized machine includes additionaldrivers that a fully-virtualized machine does not include. In stillanother embodiment, the paravirtualized machine includes the networkback-end driver and the block back-end driver included in a controlprogram 220, as described above.

Illustrated in FIG. 2B is another embodiment of a virtualizationenvironment that illustrates a Type 1 hypervisor 202. Executing on thecomputing device 201 is a hypervisor 202 that can directly access thehardware and resources within the hardware layer 210. Virtual machines232 managed by the hypervisor 202 can be an unsecure virtual machine232B and/or a secure virtual machine 232C. Whereas the virtualizationenvironment depicted in FIG. 2A illustrates a host operating system 214,the virtualization environment embodiment in FIG. 2B does not execute ahost operating system.

Further referring to FIG. 2B, and in more detail, the virtualizationenvironment includes a Type 1 hypervisor 202. Type 1 hypervisors 202, insome embodiments, execute on “bare metal,” such that the hypervisor 202has direct access to all applications and processes executing on thecomputing device 201, all resources on the computing device 201 and allhardware on the computing device 201 or communicating with the computingdevice 201. While a Type 2 hypervisor 202 accesses system resourcesthrough a host operating system 214, a Type 1 hypervisor 202 candirectly access all system resources. The Type 1 hypervisor 202 canexecute directly on one or more physical processors of the computingdevice 201, and can include program data stored in the physical memory216.

In a virtualization environment that employs a Type 1 hypervisor 202configuration, the host operating system can be executed by one or morevirtual machines 232. Thus, a user of the computing device 201 candesignate one or more virtual machines 232 as the user's personalmachine This virtual machine can imitate the host operating system byallowing a user to interact with the computing device 201 insubstantially the same manner that the user would interact with thecomputing device 201 via a host operating system 214.

Virtual machines 232 can be unsecure virtual machines 232B and securevirtual machine 232C. While FIG. 2B illustrates a secure and unsecurevirtual machine, sometimes they can be referred to as privileged andunprivileged virtual machines. In some embodiments, a virtual machine'ssecurity can be determined based on a comparison of the virtual machineto other virtual machines executing within the same virtualizationenvironment. For example, were a first virtual machine to have access toa pool of resources, and a second virtual machine not to have access tothe same pool of resources; the second virtual machine could beconsidered an unsecure virtual machine 232B while the first virtualmachine could be considered a secure virtual machine 232A. In someembodiments, a virtual machine's 323 ability to access one or moresystem resources can be configured using a configuration interfacegenerated by either the control program 220 or the hypervisor 202. Inother embodiments, the level of access afforded to a virtual machine 232can be the result of a review of any of the following sets of criteria:the user accessing the virtual machine; one or more applicationsexecuting on the virtual machine; the virtual machine identifier; a risklevel assigned to the virtual machine based on one or more factors; orany other similar criteria.

In some embodiments, unsecure virtual machines 232B may be preventedfrom accessing resources, hardware, memory locations, and programs thatsecure virtual machines 232A may access. For example, a secure virtualmachine 232C may be able to access one or more company resources, whilethe unsecure virtual machine 232B cannot access any company resources.

Illustrated in FIG. 3 is one embodiment of a system that includes acomputing device 201 executing a virtualization environment 302 and acomputing device 203 that executes a virtual desktop infrastructure(VDI) platform 310 and a performance monitoring system 316. Thevirtualization environment 302 executing on the computing device 201,can be any virtualization environment described herein. The illustratedembodiment depicts a virtualization environment 302 that includes ahypervisor 202, a control virtual machine 232A and one or moreadditional virtual machines 232B. The control virtual machine 232A caninclude a control program 220 communicating with a virtual disk 226Aassociated with metadata 322. The control program 220 can furtherinclude a disk type database 350 which can store the metadata 322associated with the virtual disks 226 of the virtualization environment302. The additional virtual machine(s) 232B can execute a guestoperating system 230A that communicates with a virtual disk 226Bassociated with metadata 322. The computing device 201 can include ahardware layer 201 that interfaces with the hypervisor 202 and thatincludes a storage subsystem 316. The other computing device 203 caninclude a VDI platform 310 that can encompass a virtual machine templatepool 318 of one or more virtual machine templates 323A-N (hereingenerally referred to as virtual machine template 323) and a group ofVDI user sessions 314 that includes one or more user sessions 304A-N(herein generally referred to a user sessions 304.) The other computingdevice 203 can also execute a virtual machine creator 330.

Further referring to FIG. 3, and in more detail, in one embodiment eachcomputing device 201, 203 can be any computing device 100 describedherein. In some embodiments, the computing devices 201, 203 can be aserver 106 or a client 102. The computing devices 201, 203 can bereferred to a first computer, a second computer, a third computer, etc.Furthermore, the computing devices 201, 203 can communicate with oneanother over a network such as any network 104 described herein. In oneembodiment one computing device 201 can be a remote computer 201, whilethe other computing device can be a local computer 203. As the computingdevices 201, 203 can be any computing machine 100 described herein, sotoo the hardware layer 210 can be any hardware layer 210 describedherein and can include any computer hardware described herein.

The virtualization environment 302 executing on the computing device201, can be any virtualization environment described herein. Inparticular, the virtualization environment 302 can include anyhypervisor configuration, or either the hypervisor configurationillustrated in FIG. 2A or the hypervisor configuration illustrated inFIG. 2B. In one embodiment, the hypervisor 202 included in thevirtualization environment 302 can be any hypervisor 202, or anyhypervisor 202 described herein.

FIG. 3 illustrates a computing machine 302 that includes avirtualization environment 302 which includes a control virtual machine232, such as any control virtual machine 232 described herein. Thecontrol virtual machine 232 executes a control program 220, such as anycontrol program 220 described herein, and can include a virtual disk226, such as any virtual disk 226 described herein. While FIG. 3illustrates a virtualization environment 302 that includes a controlvirtual machine 232A and another virtual machine 232B, in someembodiments the virtualization environment 302 can include any number ofvirtual machines 232. The virtual machines 232 can execute a guestoperating system 230, such as any guest operating system 230 describedherein, and can include a virtual disk 226, such as any virtual disk 226described herein.

The hardware layer 210, in some embodiments, can include a storagesubsystem 310. In one embodiment, the storage subsystem 316 can be asystem that includes the physical hard disks of the computing device 201and management programs for managing read/writes to those physicaldisks. In still other embodiments, the storage subsystem 316 can includeany physical storage repository of the computing device includingpermanent memory storage, temporary memory storage, disk drives (e.g.optical, floppy, tape), hard disks, external hard drives, flash memory,network-attached storage, a storage-area network, or any other storagerepository that the computing device 201 can access. When the storagesubsystem 316 optimizes storage characteristics in light of a virtualdisk 226 included in a virtual machine 232 can include determining anoptimal way to read/write to physical disks of the computing machine 201to service requests to access the virtual disk 226.

A storage subsystem 316, in some embodiments, can select a storageoptimization to optimize management of the physical memory resources. Inthese embodiments, the virtualization environment 302 does not selectthe storage optimizations but rather passes disk type data and virtualdisk 226 information to the storage subsystem 316 so that the subsystem316 can select a storage optimization. The storage subsystem 316 canhave access to different storage optimizations depending on the type ofavailable storage and the disk type of a virtual disk 226. Theseoptimizations can be made available through plugins or other modularapplications. Using information about the virtual disk 226 disk type andthe amount, type and restrictions on the physical storage of thecomputing device 201, the storage subsystem 316 can select anappropriate storage optimization.

In one embodiment, the virtual disk 226 included in each virtual machine232 can further store, include or be associated with metadata 322.Metadata 322 can be stored in a disk type database 350 within thecontrol program 220, or can be stored in any centralized storagerepository on the computing device 201. For example, the metadata 322can be stored in a storage repository within the control virtual machine232, or within a storage repository accessible by the hypervisor 202, orany other similar storage mechanism. In some embodiments, the metadata322 can be stored directly on the virtual disk(s) 226. The metadata 322can be any form of metadata such as: electronic information; electronicfiles; tags; images; documents; text files; tables; lists; or any otherform of electronic data that includes information. The metadata 322 caninclude information related to the virtual disk 226 such as the disktype, the functionalities associated with the disk, compression schemesfor the disk, or any other information related to the disk.

The metadata 322 can, in some embodiments, be stored in a disk typedatabase 350 stored within the context of the control program 220. Inother embodiments, the disk type database 350 can be stored within thecontrol virtual machine 232A or within any centralized storage area thatcan be accessed by each of the virtual machines 232 within thevirtualization environment 302 and the control program 220. The disktype database 350 can be any database, and in some embodiments can beany storage repository. The metadata 322 stored in the disk typedatabase 350 can be any type of metadata 322 described herein, and canbe metadata 322 associated with the virtual disks 226 of thevirtualization environment 302. While FIG. 3 illustrates avirtualization environment 302 on a single physical machine 201, inother embodiments the database 350 that stores the metadata 322 canstore the metadata 322 for virtual disks 226 within virtual machines 232not executing on the same physical machine 201 as the disk type database350. In other embodiments, the disk type database 350 can store metadata322 for multiple virtual disks 226 in multiple virtualizationenvironments 302, where the virtualization environments can execute ondifferent and separate physical computers. In still other embodiments,the disk type database 350 can be located on a computer or storagedevice remotely located from the computing device 201.

In one embodiment, each virtual disk 226 can have a disk type. A disktype can be a characterization of the functions performed by the virtualdisk 226. In some embodiments, the disk type can refer to a primary useof the virtual disk 226. Although the disk type can indicate a primaryfunctionality or purpose, the virtual disk 226 may, in some embodiments,perform other functions that do not fall within the typicalcharacteristics of a disk type assigned to the virtual disk 226. Thefollowing chart illustrates exemplary disk types and a typical storageoptimization for that disk type. The chart is not dispositive of everypossible disk type or storage optimization, but rather is descriptive ofembodiments of disk types and accompanying storage optimizations.

CHART 1 Disk Type/Storage Optimization Embodiments Disk Type StorageOptimization Operating System (OS) Image Create a local in-memory cacheof a common parent in a snapshot chain Non-Persistent Cache Re-orderwrites Non-Persistent Cache Early write acknowledgements Non-PersistentCache Use local storage User-Data Disk Conservative optimizations

As illustrated above in Chart 1, in one embodiment a disk that has adisk type identifying the virtual disk 226 as an OS image can beoptimized by determining that a local in-memory cache of a common parentshould be created. In this embodiment, the selected optimization can beselected based on an assumption that many OS images are created from a“gold standard” image that contains a base suite of programs. Thus,there is a substantially high likelihood that other virtual machinesexecuting in the same virtualization environment as the virtual machinethat has this virtual disk, also contain an OS image created fromsubstantially the same “gold standard” image. This characteristic of theOS image virtual disk 226 can lead to a determination that a way tooptimize the storage subsystem can be to create an in-memory per-hostcache of the disk's parent in snapshot chain. By optimizing the storagesystem 316 in this manner, the storage system 316 can now read from asingle in-memory cache of the “gold standard” disk rather than have toread from each virtual machine disk 226 within the virtualizationenvironment 302. Furthermore, by optimizing the storage subsystem 316,the system can be optimized such that virtual machine 232 boot time canbe reduced since the control program 220 need only read from a single“gold standard” cache of the OS. Similarly, the number of input/outputoperations can be reduced because rather than each process, orapplication needing to read from the storage of each virtual machine232, these processes and applications can read from the “gold standard”cache when the requested information relates to the OS image. Thereforein this embodiment, caching the virtual disk's parent image can lead tosystem optimizations such as a reduced boot time, a reduced number ofinput/output operations, a reduced number of read requests and acompartmentalization of the OS image storage into a single locationwithin the virtualization environment 302.

Also illustrated in Chart 1 is an embodiment of a disk that has a disktype identifying the virtual disk 226 as a non-persistent cache. In oneembodiment, there exist multiple ways to optimize a storage subsystemfor a non-persistent cache virtual disk 226. Chart 1 describes threeexemplary ways in which the storage subsystem 316 can be optimized. Inone embodiment, the storage subsystem 316 can be permitted to re-orderwrites issued to a virtual disk 226. Typically storage subsystems 316cannot re-order writes issued by an application to a virtual disk 226.This restriction results from the relationship between the storagesubsystem 316, the operating system and applications executing withinthe context of the operating system, to commit writes to a disk in theorder in which the writes are received. Enforcing this policy ensuressystem consistency. However, when a virtual machine boots after a crash,data stored on the disk 226 in the virtual machine 232 can be destroyed,thus it becomes safe to reorder writes to the disk 226. In some aspects,permitting the storage subsystem 316 or a disk scheduler executingwithin the storage subsystem 316 the ability to re-order writes canincrease the storage subsystem's 316 ability to service a maximum numberof input/output operations. By permitting the re-ordering of writes tothe virtual disk 226 and thereby servicing a maximum number ofinput/output operations, the number of storage targets required for anaction or process are reduced.

In another embodiment, the storage subsystem 316 can be permitted toissue early write acknowledgments when the disk type of the virtual disk226 is non-persistent cache. Typically storage subsystems 316 do notacknowledge a write to a disk until the write has been committed. Thischaracteristic of storage subsystems 316 permits applications, operatingsystems, and transaction processing systems to rely on this property ofthe storage subsystem 316 when there is a system crash or following aspontaneous shut-down event. Thus, typically a storage subsystem 316 maynot acknowledge a write to a virtual disk 226 when the write is storedin a buffer cache. After a system crash, it may be advantageous toacknowledge writes when a write is stored in a buffer cache and beforethe write is committed to the virtual disk 226 because the faster awrite acknowledgement is issued, the faster the acknowledgement can betransmitted back to the application or machine that issued the write. Afaster response time can permit applications to execute faster becausethe applications spend less time waiting from acknowledgements from thestorage subsystem 316. In still another embodiment, a non-persistentcache disk type can work in conjunction with an optimization thatdirects the storage subsystem 316 to use local storage. The data storedon a non-persistent cache disk often is low priority data that does notinclude user-critical or system-critical information, and that may beinvalidated when a virtual machine boots. Thus, in many embodiments, avirtual machine 232 may not need a disk dedicated to non-persistentcache. In these embodiments, the virtualization environment 302 mayconfigure the virtual machine 232 and the disk 226 so that a localstorage within the virtual machine 232 or the environment 302 can beused as a non-persistent cache. By permitting local storage to functionas non-persistent cache, the amount of expensive shared storage requiredto deploy the virtual machine 232 and its virtual disk 226 can bereduced, as can the load on the network.

Chart 1 also illustrates an exemplary pairing of a virtual disk 226 thathas a disk type of user-data disk, and the storage subsystem 316optimization of being conservative with the manner in which disk data ismanaged, modified, deleted and accessed. User data can often includesensitive information such as user documents and files, criticalinformation, sensitive information that requires a great deal ofsecurity and/or encryption, or other similar pieces of information.Thus, the storage subsystem 316 can be optimized such that any actionstaken with regard to the virtual disk 226 are consistent with theimportance of the user-data. In some embodiments, this optimization caninclude disabling other optimizations such as “re-order writes,” “earlywrite acknowledgements,” and user local storage.

In some embodiments, the control program 220 can establish a connectionwith the VDI platform 310 so that the control program 220 can receivevirtual machine templates 323 and other information from the VDIplatform 310. The connection, in some embodiments can be a communicationlink or a virtual channel over which the control program 220 and the VDIplatform 310 can communicate. Data and information transmitted orstreamed over the virtual channel can be encapsulated in a protocol suchas any protocol described herein. In some embodiments, the informationcan be encapsulated in a presentation level protocol such as the ICAprotocol developed by CITRIX SYSTEMS, INC. of Fort Lauderdale, Fla. Thecontrol program 220, in some embodiments, can stream or download virtualmachine information from the VDI platform 310. While FIG. 3 illustratesa system where the control program 220 establishes a communicativeconnection with the VDI platform 310, in other embodiments anotherapplication such as a VDI client can establish the communicativeconnection. In these embodiments, the other application can executewithin a control program 220, within a control virtual machine 232A orwithin the hypervisor 202.

When, in some embodiments, the control program 220 either streams ordownloads a virtual machine template 323 from the VDI platform 310, thecontrol program 220 can either execute a virtual machine using thevirtual machine template 323 data, or the control program 220 caninstantiate an instance of a virtual machine using the virtual machinetemplate 323. In some instances, the virtual machine 232 generated fromthe virtual machine template 323 includes substantially the sameinformation as the information included in the virtual machine template323. Therefore the data, the virtual disk and any applications includedin the virtual machine template 323 are included in the virtual machine232.

In one embodiment, the remote computing device 203 can execute a VDIplatform 310. The VDI platform 310 can be any platform able to implementand manage a virtual desktop infrastructure. In one embodiment, the VDIplatform 310 can communicate with other applications or programsexecuting on the computing device 203, and in some embodiments cancommunicate with a performance monitoring system 316. In otherembodiments, the VDI platform 310 can be any platform provided by theXEN DESKTOP family of products manufactured by CITRIX SYSTEMS, INC. ofFort Lauderdale, Fla. The VDI platform 310, in one embodiment, can be aplatform that establishes user sessions between users and the VDIplatform 310, and that allocates virtual machines 232, virtual desktopsand other similar resources to the user sessions. The VDI platform 310can also manage the virtual resources allocated to the user sessions andcan further perform load balancing functions to load balance the virtualresources amongst the user sessions based on a variety of criteria.

The VDI platform 310, in some embodiments, can manage a pool or group ofvirtual machine templates (herein referred to generally as the virtualmachine pool 318.) This pool or group of virtual machines can includeone, two or multiple virtual machine templates 323. In some embodiments,the virtual machine templates 323 can be virtual machines. In otherembodiments, the virtual machine templates 323 can be streamed ordownloaded into a virtualization environment 302, and can be configuredand executed to generate or instantiate a virtual machine 232. In otherembodiments, the virtual machine templates 323 can be a collection ofexecutable instructions, applications or other computing resources that,when streamed or downloaded into a virtualization environment 302, canbe configured and executed to generate or instantiate a virtual machine232.

Virtual machine templates 323, in some embodiments, can be configured toinclude a copy of metadata associated with the template when the virtualmachine template 323 is cloned. Thus, in some embodiments, when avirtual machine template 323 is cloned or copied to create a copy of thevirtual machine template 323, the metadata 322 of the virtual disk 226is preserved. Therefore when a virtual machine template 323 is streamedor downloaded to a virtualization environment 302, the virtualizationenvironment 302 preserves the metadata 322 of the virtual disk 226, andpropagates the disk type stored in the metadata 322 to the virtualmachine instance created from the virtual machine template 323.

In some embodiments, the VDI platform 310 can manage a pool or group ofuser sessions 314 (herein referred to generally as the user session pool314.) This pool or group of user sessions 314 can include one or moreuser sessions 304 created between a user and the VDI platform 310. Insome embodiments, a user session 304 can be generated when a user of aclient computing device located remote from the computing device 203,requests a virtual desktop or a virtual machine, or requests access to avirtual desktop or a virtual machine. In other embodiments, a usersession 304 can be created when a user logs onto a VDI platform 310 viaa remote client computer. Still other embodiments include user sessions304 that can be created when a user requests access to an application orresource available through a virtual machine or virtual desktop.

A user session 304, in some embodiments, can be a session between thecomputing device 203 and the user of a client machine, or a sessionbetween the VDI platform 310 and the user of a client machine. In eachof these embodiments, the client machine can be a computer that isremotely located from the computing device 203, or the client machinecan be the remote computer 201 executing the virtualization environment302. In one embodiment, the user session 304 can be created by the VDIplatform 310 in response to a user request to log onto the VDI platform310, a user request to access an application or resource, or a userrequest for a virtual machine or a virtual desktop. Users can accessaspects of the VDI platform 310 from within a user session 304.Similarly, users can interact with a virtual machine 232 assigned to auser, within the user session 304.

The computing device 203 can, in some embodiments, include a virtualmachine creator 330 that can assemble virtual machines 232 from thevirtual machine templates 318. In some instances, the virtual machinecreator 330 can stream virtual machines from the computer 203 to thevirtualization environment 302 after creating the virtual machine 232from a virtual machine template 323. While FIG. 3 illustrates a computerthat includes a virtual machine creator 330, in some embodiments, thecomputer 203 may not include a virtual machine creator 330. In theseembodiments, the control virtual machine 232 can create or otherwiseboot a virtual machine 232 from a received virtual machine template 323.The virtual machine creator 330, in some embodiments, can create thevirtual machine templates 323 based on a user request, or can annotateor otherwise modify a virtual disk 226 in a virtual machine template 323to include metadata describing the disk type of the virtual disk 226.

Illustrate in FIG. 4A is one embodiment of a method 400 for modifying avirtual disk 226 included within a virtual machine template 323. In thismethod a virtual machine template can be created (Step 402), a virtualdisk 226 in the virtual machine template 323 can be modified to includemetadata that describes the disk type (Step 404), and the virtualmachine template 323 can be allocated to a user of the virtual desktopinfrastructure 310 (Step 406).

Further referring to FIG. 4A, and in more detail, in one embodiment avirtual machine template 323 can be created (Step 402). In someembodiments the virtual desktop infrastructure 310 creates the virtualmachine template 323, while in other embodiments a virtual machinecreator 330 creates the virtual machine template 323. In still otherembodiments, a sub-program or application executing within the virtualdesktop infrastructure 310 can create the virtual machine template 323.The virtual machine template 323 can be created in response to a user'srequest for a virtual machine 232. User specifications can be used todetermine what to include in the virtual machine template 323 (e.g. disktype of a virtual disk, type of OS, applications, etc.) In oneembodiment, the virtual machine template 323 can be created in responseto a user's request for access to one or more applications or resources.

The virtual desktop infrastructure 310, upon creating the virtualmachine template, can modify a virtual disk 226 included in the virtualmachine template 323 to include metadata that describes the disk type ofthe virtual disk 226 (Step 404). In some embodiments, modifying thevirtual disk 226 can include extending the metadata 322 of the virtualdisk 226 to include a field for recording the disk type of the virtualdisk 226. In still other embodiments, modifying the virtual disk 226 caninclude annotating the virtual disk 226 to include metadata 322 thatdescribes the disk type of the virtual disk 226. In yet anotherembodiment, modifying the virtual disk 226 can include generatingmetadata 322 that maps the virtual disk 226 to a specific virtual disktype, and storing that metadata 322 on the virtual disk 226. Given thata virtual disk 226 is not a physical disk, storing the metadata 322 onthe virtual disk 226 can include storing the metadata 322 with thevirtual disk 226 data and with instructions indicating that the metadata322 should appear to be stored on a sector of the virtual disk 226.

In some embodiments, the metadata 322 can be stored in a repositoryadjunct to the virtual disk 226. When the VDI platform 310 transmits orstreams the virtual machine template 323 to the control program 220, theVDI platform 310 can also transmit or stream the metadata 322 associatedwith each virtual disk 226 included in the virtual machine template 323.The control program 220, upon receiving the virtual machine template 323and virtual disk metadata 322, can store the virtual disk metadata 322in a database such as the disk type database 350 of the control program220. In other embodiments, the control program 220 can store the virtualdisk metadata 322 in any storage repository within the virtualizationenvironment 302 that is accessible by the control program 220 and thestorage subsystem 316. One embodiment can include a VDI platform 310that stores the metadata 322 along with the virtual disk 226 in thevirtual machine template 323. In this embodiment, the control program220 can extract the virtual disk metadata 322 upon receiving the virtualmachine template 323 from the VDI platform 310. Once the control program220 extracts the virtual disk metadata 322, the control program 220 caninsert the virtual disk metadata 322 into the disk type database 350.Inserting the virtual disk metadata 322 can include generating a recordin the disk type database 350 that associates the virtual disk 226 witha disk type identified in the virtual disk metadata 322. The record canalso include: the name of the virtual machine 232 that includes thevirtual disk 226; a virtual machine 232 identifier; the name of the usersession or user to which the virtual machine is allocated, and anysimilar information.

The virtual desktop infrastructure 310 can then allocate a virtualmachine template to a user (Step 406). A virtual machine template 323can be chosen based on any type of criteria, e.g. user performancemetrics, virtual machine metrics, user requests, etc. While in someembodiments the virtual machine template is allocated based on userinformation, in other embodiments the virtual machine template 323 israndomly allocated to the user. In some embodiments, the method 400 doesnot include the step of allocating the virtual machine template to auser (Step 406) because the virtual machine template 323 is createdspecifically for that user.

Illustrated in FIG. 4B is one embodiment of a method 420 for selecting astorage optimization. A virtualization environment 302 can boot aninstance of a virtual machine 232 from a virtual machine template 323(Step 422). Upon booting the instance of the virtual machine 232, thevirtualization environment 302 can obtain and read metadata 322 of thevirtual disk 226 included in the virtual machine 232 (Step 424) todetermine the disk type of the virtual disk 226 (Step 426). Thevirtualization environment 302 can then pass the disk type informationto the storage subsystem 316 (Step 428) which can then select a storageoptimization based on the received disk type (Step 430). Upon selectingthe storage optimization, the storage subsystem 316 can attach optimizedstorage to the virtual machine instance 232 (Step 432).

Further referring to FIG. 4B, and in more detail, in one embodiment thevirtualization environment 302 boots an instance of a virtual machine232 (Step 422). The virtual machine instance 232 can be created and canbe based on a virtual machine template 323 transmitted to thevirtualization environment 302 from the virtual desktop infrastructure310. Thus, when a virtual desktop infrastructure 310 assigns a virtualmachine template 323 to a user, the virtual desktop infrastructure 310can then transmit the virtual machine template 323 to the virtualizationenvironment 302. Upon receiving the virtual machine template 323, thevirtualization environment 302 can boot a virtual machine 232 from thevirtual machine template 323.

One a virtual machine 232 is booted from the virtual machine template323, the virtualization environment 302 can obtain and read the metadata322 of each virtual disk 226 included in the virtual machine 232 (Step424). Obtaining the metadata 322 can include reading the metadata 322from a storage location specified by the virtual disk 226. In otherembodiments, reading the metadata 322 can include retrieving themetadata 322 from a virtual storage sector on the virtual disk 226,where the virtual storage section corresponds to a physical storagerepository on the computing machine.

While FIG. 4B illustrates a method 420 where the metadata is obtainedand read, in other embodiments the control program 220 does not obtainthe metadata but rather queries the disk type database 350 for disk typeinformation associated with the virtual machine 232. This query caninclude relevant information that can be used to look-up the disk typeof one or more virtual disks 226 included in the booted virtual machine232, such as: a virtual machine name or other identifier; a diskidentifier; and a user or user session identifier.

Upon retrieving, obtaining or otherwise reading the metadata 322 foreach virtual disk 226 of a virtual machine 232, the virtualizationenvironment 302 can determine the disk type of the virtual disk 226(Step 426) and pass the disk type to the storage subsystem 316 (Step428). In some embodiments, the virtualization environment 302 can passthe disk type to the storage subsystem 316 via the hypervisor 202 andusing an application program interface that interfaces with the storagesubsystem 316 of the computer. In other embodiments, the virtualizationenvironment 302 can pass the disk type to the storage subsystem 316using fields in a simple messaging application programming interface.

The storage subsystem 316 can receive the disk type(s) from thevirtualization environment 302, and can select a storage optimizationusing the disk type information (Step 430). In some embodiments, thestorage subsystem 316 can select optimizations according to any of thecombinations described herein. In other embodiments, the storagesubsystem 316 can select a storage optimization according to thosestorage optimizations appropriate for a particular disk type.

While certain exemplary embodiments have been described and shown in theaccompanying drawings, it is to be understood that such embodiments aremerely illustrative of and not restrictive on the methods and systemsdescribed herein. Additionally, it is possible to implement the methodsand systems described herein or some of its features in hardware,programmable devices, firmware, software or a combination thereof. Themethods and systems described herein or parts of the methods and systemsdescribed herein may also be embodied in a processor-readable storagemedium or machine-readable medium such as a magnetic (e.g., hard drive,floppy drive), optical (e.g., compact disk, digital versatile disk,etc), or semiconductor storage medium (volatile and non-volatile).

1-20. (canceled)
 21. A method for modifying a virtual disk within avirtualization environment using metadata indicating a disk type of thevirtual disk, the method comprising: creating, by a virtual desktopinfrastructure executing on a computing machine, a virtual machinetemplate comprising at least one virtual disk; modifying, by the virtualdesktop infrastructure, the at least one virtual disk to comprisemetadata describing the disk type of the at least one virtual disk; andallocating, by the virtual desktop infrastructure, the virtual machinetemplate to a user.
 22. The method of claim 21, further comprisingcopying the virtual machine template to create a second virtual machinetemplate comprising the at least one virtual disk comprising themetadata describing the disk type.
 23. The method of claim 21, furthercomprising obtaining the metadata of the at least one virtual disk by astorage subsystem of the virtualization environment.
 24. The method ofclaim 23, further comprising selecting a storage optimization for the atleast one virtual disk based in part on the disk type described in themetadata by the storage subsystem.
 25. The method of claim 24, whereinselecting the storage optimization further comprises selecting a storageoptimization based in part on the disk type and a specific disk storagetype.
 26. The method of claim 21, wherein modifying the virtual disk tocomprise metadata describing the disk type further comprises modifyingthe virtual disk to comprise metadata describing an operating systemimage disk type.
 27. The method of claim 21, wherein modifying thevirtual disk to comprise metadata describing the disk type furthercomprises modifying the virtual disk to comprise metadata describing anon-persistent cache disk type.
 28. The method of claim 21, whereinmodifying the virtual disk to comprise metadata describing the disk typefurther comprises modifying the virtual disk to include metadatadescribing an image customization disk type.
 29. The method of claim 21,wherein allocating the virtual machine template to the user is basedupon at least one of: user performance metrics, virtual machine metrics,user requests and user information.
 30. The method of claim 21, furthercomprising attaching an optimized storage according to the virtualmachine.
 31. A system for modifying a virtual disk within avirtualization environment using metadata indicating a disk type of thevirtual disk, the system comprising: a virtual desktop infrastructureexecuting on a computing machine to: create a virtual machine templatecomprising at least one virtual disk, modify, responsive to creating thevirtual machine template, the at least one virtual disk to comprisemetadata describing a disk type of the at least one virtual disk; andallocate to a user the virtual machine template.
 32. The system of claim31, wherein the virtual desktop infrastructure copies the virtualmachine template to create a second virtual machine template comprisingthe at least one virtual disk comprising the metadata describing thedisk type.
 33. The system of claim 31, wherein a storage subsystem ofthe virtualization environment obtains the metadata of the at least onevirtual disk.
 34. The system of claim 33, wherein the storage subsystemof the virtualization environment selects a storage optimization for theat least one virtual disk based in part on the disk type described inthe metadata.
 35. The system of claim 34, wherein the storage subsystemselects the storage optimization based in part on the disk type and aspecific disk storage type.
 36. The system of claim 31, wherein themetadata describes an operating system image disk type.
 37. The systemof claim 31, wherein the metadata describes a non-persistent cache disktype.
 38. The system of claim 31, wherein the metadata describes animage customization disk type.
 39. The system of claim 31, wherein thevirtual desktop infrastructure allocates the virtual machine template tothe user based upon at least one of: user performance metrics, virtualmachine metrics, user requests and user information.
 40. The system ofclaim 31, wherein the storage subsystem attaches a storage optimizedaccording to the selected storage optimization.